Constrained groove pressing for sheet metal processing

Constrained groove pressing (CGP) is a modern technique for developing ultrafine grain structures in sheet metals for inducing superior material properties. In CGP, the sheet metal specimens are subjected to repetitive corrugating and straightening under the plane strain deformation condition by utilizing alternate pressing with the asymmetrically grooved dies and flat dies. This induces a great amount of plastic strain in the sheet metal specimen without changing its initial dimensions. Over the last few years, CGP has gained significant importance for it being one of the most suitable techniques to fabricate sheet metals with superior and attractive properties. CGP can effectively refine the grain structure to a sub-micrometre level and at times, even to a nanometer level. Materials processed by CGP exhibit very high strength, high hardness and many other desirable properties. Numerous investigations were made on different materials like aluminium, copper, low carbon steel and nickel, and their properties were well documented in the scientific literature. This review summarizes most of the scientific results that were obtained by applying CGP to various materials and gives an outline of the applications of CGP in various industries. This review also discusses about the future scope of research on CGP and its benefits.